git: c4c375354287 - stable/15 - system(3): Address test robustness issue

The branch stable/15 has been updated by des:

URL: https://cgit.FreeBSD.org/src/commit/?id=c4c375354287d6eb9fa71ebb5d9fd6a765faf795

commit c4c375354287d6eb9fa71ebb5d9fd6a765faf795
Author:     Dag-Erling Smørgrav <des@FreeBSD.org>
AuthorDate: 2026-03-09 20:41:04 +0000
Commit:     Dag-Erling Smørgrav <des@FreeBSD.org>
CommitDate: 2026-03-11 13:16:10 +0000

    system(3): Address test robustness issue
    
    Don't assume that SIGINT and SIGQUIT are set to SIG_DFL at the start
    of the test.  Instead, retrieve their current dispositions and verify
    that they are restored at the end of the test.
    
    MFC after:      1 week
    Sponsored by:   Klara, Inc.
    Reviewed by:    kevans
    Differential Revision:  https://reviews.freebsd.org/D55709
    
    (cherry picked from commit 48368f702423742b2a7dff7ad3191625e8bf26f0)
    
    system(3): Fix brain glitch in previous commit
    
    We were saving SIGINT twice instead of SIGINT and SIGQUIT.
    
    Also restore original order of operations (SIGINT then SIGQUIT), which
    matches the order in which they're discussed in the POSIX description
    of system(3).
    
    MFC after:      1 week
    Sponsored by:   Klara, Inc.
    Fixes:          48368f702423 ("system(3): Address test robustness issue")
    
    (cherry picked from commit 863b5c137a98d29dc6964cba0e0c4fe2a8bebab8)
---
 lib/libc/tests/stdlib/system_test.c | 38 ++++++++++++++++++++++++++-----------
 1 file changed, 27 insertions(+), 11 deletions(-)

diff --git a/lib/libc/tests/stdlib/system_test.c b/lib/libc/tests/stdlib/system_test.c
index b6a31583d52d..9e556f257791 100644
--- a/lib/libc/tests/stdlib/system_test.c
+++ b/lib/libc/tests/stdlib/system_test.c
@@ -92,6 +92,12 @@ system_thread(void *arg)
 	return ((void *)(intptr_t)system(cmd));
 }
 
+static inline int
+sigcmpset(const sigset_t *a, const sigset_t *b)
+{
+	return (memcmp(a, b, sizeof(sigset_t)));
+}
+
 ATF_TC(system_concurrent);
 ATF_TC_HEAD(system_concurrent, tc)
 {
@@ -99,7 +105,8 @@ ATF_TC_HEAD(system_concurrent, tc)
 }
 ATF_TC_BODY(system_concurrent, tc)
 {
-#define N 3
+	enum { N = 3 };
+	struct sigaction sigint, sigquit, sigact;
 	sigset_t normset, sigset;
 	pthread_t thr[N];
 	char fn[8];
@@ -119,8 +126,10 @@ ATF_TC_BODY(system_concurrent, tc)
 		ATF_REQUIRE_EQ(0, symlink(fn, fn));
 	}
 
-	/* Get the current and expected signal mask */
-	sigprocmask(0, NULL, &normset);
+	/* Save the current signal dispositions */
+	ATF_REQUIRE_EQ(0, sigaction(SIGINT, NULL, &sigint));
+	ATF_REQUIRE_EQ(0, sigaction(SIGQUIT, NULL, &sigquit));
+	ATF_REQUIRE_EQ(0, sigprocmask(0, NULL, &normset));
 
 	/* Spawn threads which block on these files */
 	for (int i = 0; i < N; i++) {
@@ -140,10 +149,12 @@ ATF_TC_BODY(system_concurrent, tc)
 	/* Release the locks */
 	for (int i = 0; i < N; i++) {
 		/* Check the signal dispositions */
-		ATF_CHECK_EQ(SIG_IGN, signal(SIGINT, SIG_IGN));
-		ATF_CHECK_EQ(SIG_IGN, signal(SIGQUIT, SIG_IGN));
+		ATF_REQUIRE_EQ(0, sigaction(SIGINT, NULL, &sigact));
+		ATF_CHECK_EQ(SIG_IGN, sigact.sa_handler);
+		ATF_REQUIRE_EQ(0, sigaction(SIGQUIT, NULL, &sigact));
+		ATF_CHECK_EQ(SIG_IGN, sigact.sa_handler);
 #ifndef PROCMASK_IS_THREADMASK
-		sigprocmask(0, NULL, &sigset);
+		ATF_REQUIRE_EQ(0, sigprocmask(0, NULL, &sigset));
 		ATF_CHECK(sigismember(&sigset, SIGCHLD));
 #endif
 
@@ -156,11 +167,16 @@ ATF_TC_BODY(system_concurrent, tc)
 	}
 
 	/* Check the signal dispositions */
-	ATF_CHECK_EQ(SIG_DFL, signal(SIGINT, SIG_DFL));
-	ATF_CHECK_EQ(SIG_DFL, signal(SIGQUIT, SIG_DFL));
-	sigprocmask(0, NULL, &sigset);
-	ATF_CHECK_EQ(0, memcmp(&sigset, &normset, sizeof(sigset_t)));
-#undef N
+	ATF_REQUIRE_EQ(0, sigaction(SIGINT, NULL, &sigact));
+	ATF_CHECK_EQ(sigint.sa_handler, sigact.sa_handler);
+	ATF_CHECK_EQ(sigint.sa_flags, sigact.sa_flags);
+	ATF_CHECK_EQ(0, sigcmpset(&sigint.sa_mask, &sigact.sa_mask));
+	ATF_REQUIRE_EQ(0, sigaction(SIGQUIT, NULL, &sigact));
+	ATF_CHECK_EQ(sigquit.sa_handler, sigact.sa_handler);
+	ATF_CHECK_EQ(sigquit.sa_flags, sigact.sa_flags);
+	ATF_CHECK_EQ(0, sigcmpset(&sigquit.sa_mask, &sigact.sa_mask));
+	ATF_REQUIRE_EQ(0, sigprocmask(0, NULL, &sigset));
+	ATF_CHECK_EQ(0, sigcmpset(&sigset, &normset));
 }
 
 ATF_TP_ADD_TCS(tp)